Polymerizable esters of acrylic and methacrylic acid and polymers thereof



POLYMERIZABLE ESTERS F ACRYLIC AND METHACRYLIC A CID AND POLYMERS THEREOF James C. Fang, Sharon Hill, Pa., assignor to E. I. du

Pont de Nemours and Company, Wilmington, Deli, a

corporation of Delaware M o H W No Drawing. Filed'Mar. 22, 1956, Ser. No. 573,094

19 Claims. (Cl. 260-77.5)

This invention relates to polymerizable esters of acrylic and methacrylic acids and to homopolymers and copolymers thereof. 7 V v U H The polymerizable monomeric esters of this invention have the general formula:

in which R is H or CH, and n is an integer having a value of 1 to 4 inclusive. Thus they are the acrylic or methacrylic acid esters of the cyclic carbonates of the alpha, beta, omega alkane-triols which contain 3 to 6 carbon atoms in the alkane chain, i.e. glycerol to 1,2,6- hexanetriol. ,7

The esters of this invention readily polymerize by vinyl or addition polymerization through the terminal CH +C group to form homopolymers or, when other CH =C containing monomers are included, the corresponding copolymers.

The esters of this invention can be prepared from acrylic or methacrylic acid, or a lower alkyl ester thereof, and the cyclic carbonate of an alkane triol in accordance with the general esterification reaction:

R is H, CH3, C2H5, C3H7 ciiHg pre ferred form of R being CH or C l-l H v The preferred acrylic compounds for use in the above reaction are methyl acrylate, methyl methacrylate; ethyl acrylate and ethylmethacrylate. I U

The cyclic carbonates of the alkane triols used in the above reaction are available on the market or can be prepared by known methods, such as by careful r 'eac'-" tion of the alkane trio] with a cyclic alkylene' carbonate, such as ethylene carbonate. Y

The esterification reaction mentioned above is carried out at an elevated temperature, preferably a tempera titre above the boiling point of the reaction m ll tiire' but below the boiling point of the desired product so hat the by-product, R'OH, can be removed by distillation; thus forcing the reaction to completion. A convenient method involves using an excessof a lower alkyl acrylate and distilling off a mixture" thereof with the R'OH alcohol, whereby a maximum conversion of alkane triol carbonate to the desired ester is obtained. The reaction is carried out preferably inthe presence of an esterification catalyst, eg. an alkali metal alkox'ide', oxidelhy dride or hydroxide or litharge,- and a polymerization inhibitor, e.g'. phe'nothiaz'i'ne hydroquinone', tertiary bu'tyl catechol er various amines.

-Thej 'ster'ification reaction is car'ried ont" preferably a high cefieentration mass reaction in" the absence of 2 inert bpt it can be done in the presence of an inert solvent like dioxane.

Following th este -licatio ireaction,

be carried to the desired degree, preferably by fractional distillation under reduced pressure whereby q a crude ester of this invention having a wide boiling range an be obtained ora substantially pure product having 'a narrow boiling range can be obtained. ,For example, either a crude 'rnethacrylate ester of glyceryl carbon e having a boiling range of about 13,0 C. at 0.3 mm. Hg or a substantially pure ester 'having fa bo range of about 119-121 C. at 0.1 mm. can 7 mined as desired. Volatile polymeriia ion inhib tgrs which distill over with the ester can be removed by wane known means if desired. 7 7 W In all of the process steps involved inmaking me; esters of this invention, the temperatures should be kep t below the point where pyrolysis, yielding CQ is en:- countered. Sub-atmospheric pressure is a convenient means of avoiding high temperatures. v

The esters of this invention can be polyrneri'zed known methods applicable to vinyl and acrylic type menomers. Polymerization canbe carried out in bulk, solu;

tion, suspension or emulsion; the pre ence; or ab of well-known proportions of well-known pol tion catalysts e.g. ben'zoyl peroxide, tejrtiar drop'eroxide', tertiary butyl perb'en'zoate, a

esters of acrylic or methacrylic acid suchas methyl Inet arcylate, ethyl acrylate', octyl acrylate and benzy'l a'cr late; acrylamides such as methajcrylarnide; vinylest 1 such as vinyl chloride and vinyl acetate; vinyliderie' chlo ride; acrylonitrile; allyl cornpou nds such as diallyla'di, pate; vi nyl aryl compoundssuch as styrene and div y benzene; and other unsaturated co'tnpou'n'ds mi" b" a ene' and maleic anhydride. All,of these monomers do; not necessarily copolyme'rize with the new esters of thisinvention in all proportions of such monomer to new ester. However, the copolymers of this invention can be made to contain from, a v'ery srnall bfit effective amount of a new ester of this' iriverition, e'.g the time}; of 0.5% or 1.0%, to almost entirely new ester eg l. the order f 99% or 99.5%, he'percema es" representing amount of new ester based on the total material edpalya merized. v t H It is to be understood that copolyriiers can also be n'iaae' from a mixture of two or more of the new esters with or without additional monomers or from only one new este'r with two or more other monomers. i

It is likewise to be understood that homopolynieria tion or copolymerization of the products of l th istin tion can be controlled and the character of the pro can be varied by techniques well-known.'n theiad diti 9 IF- 933303215.i LQIPQQPMEQJYQQKL iation tliesolvent can be selected from hydrocarbons, ketones, esters and the like, or mixtures thereof, so that nie resntirg polymer remains in solution or precip out of solution asitis' terri ed; d ngtrijgfppgnj aqueous emulsion or;

2,967,173 I a A invention. but it is not limited thereby. Unless otherwise specified, the parts and percentages are by weight.

These components were mixed thoroughly and were placed in a reaction vessel equipped with an agitator, thermometer, nitrogen inlet, and a combination fractioning column, take-off head, and condenser vented to the atmosphere. The system was swept with nitrogen, and a slow stream of nitrogen was passed through the apparatus during the remainder of the process.

The charge was refluxed (liquid temperature approximately 100-102 C.) for about 4.5 hours. Then methyl alcohol was distilled off with unreacted methyl methacrylate until the distillate was substantially free of methyl alcohol, as indicated by refractive index measurements. This required about two hours, during which the temperature rose to about 106 C.

The resulting solution was subjected to a vacuum (approximately 20 mm. Hg) and was carefully heated to drive off unreacted methyl methacrylate.

The residue was dissolved in benzene and was washed several times with 30% aqueous CaCl to remove unreacted glyceryl carbonate and then several times with 15% aqueous NaOH to remove the hydroquinone. Finally the benzene was removed by vacuum distillation, yielding about 200 parts of crude methacrylate ester of glyceryl carbonate.

The crude was purified by adding 2 parts of hydroquinone and distilling under vacuum. The purified portion boiling between 116 C. at 0.3 mm. Hg and 131 C. at 0.4 mm. Hg was retained. Most of this product had a boiling range of 119-121 C. at 0.1 mm. Hg. The hydroquinone was removed by dissolving the product in ethylene chloride and hexane, washing with aqueous NaOH, and finally removing the solvent by vacuum distillation. The product was identified as predominantly methacrylate ester of glyceryl carbonate by analysis (found 50.50% C, 6.23% H, 43.27% 0; theoretical 51.60% C, 5.37% H, 43.03% 0).

Example 2 Examples 3-6 Copolymers of the methacrylate ester of glyceryl carbonate and various other monomers containing the CH =C group were prepared by placing the following charges in separate vessels, covering with a nitrogen atmosphere, sealing, and tumbling in a water bath at 85 C. for 16 hours:

Parts by Weight Examnln 3 4 6 6 Methacrylate ester of glyceryl carbonate.-- 1 10 Acrylonltrile Butadicne. Toluene Distilled water 1 Potassium persvlfate (X 8 0 1.0

Alpha, alpha-azohis(isobutyronitrile) 1.0 0.5 Sodium lauryl sulfate 5 1. 5

Examples 3 and 4 illustrate polymerization in solution. The copolymer of Example 3 remained soluble in the toluene and yielded a syrupy solution, which was useful without further modification as a clear coating composition. The copolymer of Example 4 was insoluble in the toluene and occurred as a particulate precipitate.

Examples 5 and 6 illustrate polymerization in aqueous emulsion. The resulting copolymers occurred as particulate precipitates.

The processes, the ingredients and the proportions used in these examples can be varied as previously described.

The acrylate analog (referring to the general formula; R is H, n=l) of the product of Example 1 is prepared by substituting an equivalent amount of a lower alkyl acrylate, preferably methyl acrylate or ethyl acrylate, for the methyl methacrylate in Example 1. The resulting product can be used in polymerization processes, as in Examples ,2-6, to provide a homopolymer and copolymers of this invention.

The 1,2,6-hexanetriol analog (referring to the general formula; R is CH n=4) of the product of Example 1 is prepared by substituting an equivalent amount of the carbonate of 1,2,6-hexanetriol, i.e.

0 for the glyceryl carbonate in Example 1. The resulting product can be used in polymerization processses, as in Examples 2-6 to provide a homopolymer and copolymers of this invention.

Likewise, the other polymerizable esters of this inverttion, in which R is H or CH and 12:1, 2, 3 0r 4, can be made byusing the appropriate ingredients in the general process illustrated by Example 1, which obvious ly can be modified to use acrylic or methacrylic acid in place of an ester thereof. All of the resulting esters can be used in polymerization processes, as illustrated in Examples 2-6, to provide homopolymers and copolymers of this invention.

Since the esters of this invention are readily polymerizable, it is preferred to have present during manufacture and storage enough of an inhibitor, such as hydroquinone, tertiary butyl catechol, pyrogallol and the like, to prevent an undesirable amount of polymerization. The inhibitor can be removed or inactivated, if desired, before the esters are polymerized. However small amounts of inhibitor can be tolerated, or may even be desirable, in some polymerization processes.

By varying catalyst concentration, temperature, ratio of monomers to each other, ratio of monomers to inert solvent or dispersion medium, and similar controlling factors, homopolymers and copolymers of this invention can be made to have a wide range of physical and chemical properties. The polymers are suitable for use in clear and pigmented coating compositions (solution and dispersion types), adhesives, and molding and casting resins. The polymers can be foamed and/or crosslinked by pyrolyzing, whereby carbon dioxide is split off. The polymers can also be crosslinked by treating, e.g. by heating, with polyfunctional compounds capable of reacting with the structure such as dihydroxy, dicarboxy, and diamine compounds.

The new esters of this invention are also useful as chemical intermediates. For example, glycidyl methacrylate can be made by pyrolyzing the methacrylate ester of glyceryl carbonate under carefully controlled conditions, preferably in the presence of a polymerization inhibitor, and analogous reactions can be carried out with the other new esters of this invention.

The preferred new esters of this invention are the acrylate and the methacrylate of glyceryl carbonate, largely for economic reasons; and the preferred homopolymers and copolymers are those derived from these two esters.

Many widely dilferent embodiments of this invention can be made Without departing from the spirit and scope thereof. Therefore it is not intended to be limited except as indicated in the appended claims.

The embodiments of this invention in which an ex clusive property or privilege is claimed are:

1. A polymerizable ester having the general formula:

in which R is a member of the class consisting of H and CH and in which n is an integer having a value of 1 to 4, inclusive.

2. A polymerizable ester having the formula:

oHi--( 3 :000HiCH-0Ha 0 II o 3. A polymerizable ester having the formula:

CH=OCO0(CH)5CHCH1 4. A polymerizable ester having the formula:

CHz=CCOO(CHz)4CH-CH3 5. A polymerizable ester having the formula:

CHF(3CO0CH2CHCH:\

7. A homopolymer of an ester of claim 1.

8. A homopolymer of an ester of claim 2.

9. A homopolymer of an ester of claim 3.

10. .A homopolymer of an ester of claim 4.

11. A homopolymer of an ester of claim 5.

12. A homopolymer of an ester of claim 6.

13. A copolymer of an ester of claim 1 and another polymerizable compound containing the CH =C group.

14. A copolymer of an ester of claim 2 and another polymerizable compound containing the CH =C group.

15. A copolymer of an ester of claim 3 and another polymerizable compound containin gthe CH =C group.

16. A copolymer of an ester of claim 4 and another polymerizable compound containing the CH =C group.

17. A copolymer of an ester of claim 5 and another polymerizable compound containing the CH =C group.

18. A copolymer of an ester of claim 6 and another polymerizable compound containing the CH =C group.

19. A compound of the formula wherein R is a member of the class consisting of a hydrogen atom and a methyl group and n is an integer having a value from one to four, inclusive.

References Cited in the file of this patent UNITED STATES PATENTS 2,384,124 Muskat et a1. Sept. 4, 1945 2,511,942 Prichard June 20, 1950 2,522,680 Kropa et al Sept. 19, 1950 2,524,432 Dorough Oct. 3, 1950 OTHER REFERENCES Brunson et al.: Journal American Chem. Soc., vol. 74 (1952), pp. 2100-1.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2 967,173 January 3, 1961 James C. Fang It is hereby certified that error eppears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 6, for "150.0" read 1500 Signed and sealed this 16th day of May 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

1. A POLYMERIZABLE ESTER HAVING THE GENERAL FORMULA 